Choosing the Right DSP for Your Project

It can be argued that quality audio is the most critical component in the effectiveness of an AV system. More so than inadequate video or complex operation, unintelligible audio makes it very difficult—or impossible—to convey a message. The inability to hear a presentation or participate conference call can be one of the most frustrating and embarrassing situations that a user will encounter.

Audio systems are designed through basic principles of AV, including selection of the proper type and quantity of microphones and speakers, understanding distance measurements for placement, and following installation best practices. And, in most cases, a programmable digital signage processor (also known as an audio DSP) is utilized to configure the audio paths, mixing, gain structure, and echo cancellation. Since the audio DSP is the component that requires the most setup in the audio chain, it can also be linked to the cause of most audio issues if not programmed properly.

Audio DSPs are software-driven devices that are considered “programmable”; however, the skillset required is more of configuration and is better performed by AV system designer or audio engineer than a traditional programmer. It is critical that the person responsible for programming the audio DSP has thorough knowledge of audio and is familiar (or better yet, certified) in the brand of audio DSP that is specified in a project. Like control system programming, the software, hardware components, and approach required to program an audio DSP vary from manufacturer to manufacturer.

Most audio DSP platforms can be categorized in two flavors: open architecture and closed architecture. Open architecture refers to the lack of predefined structure in the design in the audio system. For open-architecture systems, programming of the audio DSP starts with a blank canvas and provides ultimate flexibility in the design of the audio flow and processing, resulting in more options and support for more variations. However, it requires more skill, discipline, and knowledge to avoid pitfalls.

Closed-architecture systems are less flexible, but easier to design due to static components within the audio system that are always present and set up in advance. Although these systems may be easier to program and have fewer variables, the rigidity of their structure may not suit all needs or applications.

Similar to control systems, selecting the appropriate audio DSP solution needs to incorporate a number of factors, including the system application, the size and layout of the space, user requirements, and future considerations. For example, the audio DSP that would be a great fit for a meeting room, conference room, or classroom may not the be same as the audio DSP that would be ideal for a multipurpose room, event space with room combining, theater, or stadium.

Most audio DSPs are scalable; however, there can be limitations to the number of pathways between units, processing power, and availability of echo cancellation. Lastly, the ability to support Dante or other audio network protocols is a valuable feature for interoperability and expansion.

In addition to hardware specifications and installation parameters, an audio DSP program or configuration takes into consideration the following factors that need to be defined in software where they apply.

  • Presentation audio routing
  • Audio conference mixing and echo cancellation
  • Videoconference mixing and echo cancellation
  • Audio conference combined with a videoconference
  • Speech reinforcement
  • Mix minus voice lift
  • Room-combining presets
  • Compensation for room design and acoustics
  • Integration with a control system
  • User controls and requirements

In addition to programming the audio DSP to satisfy the system requirements, the audio levels need to be set up and calibrated to provide optimal performance. This important service of audio commissioning is often overlooked due to lack of time, knowledge, or scope requirements. Since audio depends very much on the specifics of physical space and environment, proper audio DSP programming accompanied by precise field commissioning is what is required to ensure success.

There is more than meets the eye when it comes to delivering an effective audio system. Considering how important audio is to the success of a presentation, meeting, or event, proper programming and commissioning of an audio DSP needs to be handled effectively and looked at as a priority.

As with control system programming, it is critical to identify a specialized and reliable resource to ensure your audio system will perform effectively and efficiently. The idea that any field tech or programmer can provide audio DSP programming is not a good solution.

Don’t put your meeting, presentation, or conference call at risk with an unproven field technician or programmer who is trying to figure out how to program the audio DSP on the fly. Instead, enlist the skills of a specialized audio DSP professional and have confidence that users will communicate with comfort and clarity.

Steve Greenblatt, CTS, is president and founder of Control Concepts, a provider of specialized software and services for the audiovisual industry.

Want to Learn to Program DSPs?

Many industry manufacturers sponsor training programs to learn more about DSP and the AV industry at large. For example, Biamp offers a wide variety of certification training in a number of formats to fit any schedule, no matter how hectic. The company hosts live webinars, on-demand self-paced courses, and more advanced hands-on, instructor-led sessions providing the information and the knowledge to build the solutions that customers are seeking. Biamp’s trainings cover a broad gamut, from topic specific subjects to become more fluent in networking, VoIP and DSP, to individual product training from Tesira to Vocia.
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